Natural coffee flavor by fermentation

Abstract

A buttery and/or winey flavor of which diacetyl and acetoin are the major flavor constituents is produced by the fermentation of a coffee substrate. The process involves forming a nutrient media containing water and soluble coffee solids as the nutrient component, the soluble solids concentration being at least 0.5%. A microorganism which is either a strain of lactic acid producing bacteria or yeast capable of producing diacetyl is added the nutrient media and the combination is mixed and simultaneously placed into an environment of a pH of from 4.0 to 7.0, a temperature of from 16° to 37° C., for a period of time effective to produce diacetyl and aeration conditions wherein the nutrient media contains sufficient oxygen to allow for diacetyl production. The aforementioned process will produce diacetyl and acetoin. The diacetyl which is produced is recovered and or concentrated and added to a coffee product.

We claim: 
     
       1. A process for producing a natural buttery flavor, winey flavor or combination buttery and winey flavor of which diacetly and acetoin are the major flavor constituents from a coffee substrate which comprises: (a) forming a nutrient media containing water and soluble coffee solids as the sole nutrient component, said soluble coffee solids concentration of at least 0.5%;   (b) adding a diacetyl producing microorganism which is either a strain of lactic acid producing bacteria or yeast to said nutrient media, wherein said microorganism will ferment the coffee solids to produce said natural flavor; and   (c) mixing the microorganism and nutrient media of step (b) and allowing said microorganism to ferment in the mixture for a period of time effective to produce diacetyl at a pH of from 4.0 to 7.0 and a temperature of from 16° to 37° C. under aeration conditions wherein the nutrient media contains sufficient oxygen to allow for diacetyl production during said fermentation to produce a fermented coffee substrate containing sufficient diacetyl and acetoin to provide said flavor.   
     
     
       2. The process of claim 1 wherein the microorganism is a lactic acid producing bacteria. 
     
     
       3. The process according to claim 1 wherein the nutrient media additionally contains pyruvic acid or salt of pyruvic acid at a level of from 0.1% to 1.0%. 
     
     
       4. The process according to claim 3 wherein the nutrient media contains from 0.5% to 0.8% pyruvic acid. 
     
     
       5. The process of claim 1 wherein the soluble coffee solids is provided by a coffee material selected from the group consisting of green extract, grounds green coffee, coffee by products, hydrolyzed spent ground roast and ground coffee, brown extract, and combinations thereof. 
     
     
       6. The process of claim 1 wherein the substrate composition contains from 0.75% to 25% soluble solids concentration. 
     
     
       7. The process of claim 5 wherein the coffee substrate is green extract. 
     
     
       8. The process of claim 1 wherein the period of time ranges from 8 to 96 hours. 
     
     
       9. The process according to claim 1 wherein the temperature is from 27° to 32° C. 
     
     
       10. The process according to claim 1 further comprising the steps of separating out the diacetyl produced in step (c) and adding the diacetyl to a coffee product or imitation coffee product to enhance a buttery flavor in said product. 
     
     
       11. The process according to claim 10 wherein the level of addition of the diacetyl to the coffee product ranges from 0.1 ppm to 1.5 ppm on an as-consumed basis. 
     
     
       12. The process according to claim 10 wherein the separated diacetyl is added to a soluble coffee product at a level of from 10 to 150 ppm diacetyl on a dry weight basis. 
     
     
       13. The process according to claim 1 further comprising the steps of combining the diacetyl and nutrient media of step (c) with a concentrated coffee extract and spray drying or freeze drying the combination obtained therefrom to produce a soluble coffee. 
     
     
       14. The process according to claim 13 wherein the soluble coffee contains from 10 to 150 ppm diacetyl on a dry weight basis. 
     
     
       15. The process according to claim 1 further comprising the steps of separating out the diacetyl produced in step (c) and combining said diacetyl with a concentrated coffee extract and spray drying or freeze drying the combination obtained therefrom to produce a soluble coffee. 
     
     
       16. The process according to claim 15 wherein the soluble coffee contains from 10 to 150 ppm diacetyl on a dry weight basis. 
     
     
       17. The process according to claim 10 wherein the separated diacetyl is added to roast and ground coffee at a level of from 50 to 400 ppm on a dry weight basis. 
     
     
       18. The product produced by the process of claim 12. 
     
     
       19. A process for producing a natural buttery flavor, winey flavor or combination buttery and winey flavor of which diacetyl and acetoin are the major flavor constituents from a coffee substrate which comprises: (a) forming a nutrient media consisting essentially of soluble coffee solids and water containing a soluble coffee solids concentration of at least 0.5%;   (b) adding a diacetyl producing microorganism which is either a strain of lactic acid producing bacteria or yeast to said nutrient media, wherein said microorganism will ferment the coffee solids to produce said natural flavor; and   (c) mixing the microorganism and nutrient media of step (b) and allowing said microorganism to ferment in the mixture for a period of time effective to produce diacetyl at a pH of from 4.0 to 7.0 and a temperature of from 16° to 37° C. under aeration conditions wherein the nutrient media contains sufficient oxygen to allow for diacetyl production during said fermentation to produce a fermented coffee substrate containing sufficient diacetyl and acetoin to provide said flavor.   
     
     
       20. The process of claim 19 wherein the microorganism is a lactic acid producing bacteria. 
     
     
       21. The process of claim 19 wherein the soluble coffee solids is provided by a coffee material selected from the group consisting of green extract, ground green coffee, coffee by products, hydrolyzed spent grounds, roast and ground coffee, brown extract, and combinations thereof. 
     
     
       22. The process of claim 21 wherein the substrate composition contains from 0.75% to 25% soluble solids concentration. 
     
     
       23. The process of claim 22 wherein the coffee substrate is green extract. 
     
     
       24. The process of claim 19 wherein the period of time ranges from 8 to 96 hours. 
     
     
       25. The process according to claim 19 wherein the temperature is from 27° to 32° C. 
     
     
       26. The process according to claim 19 wherein the nutrient media additionally contains pyruvic acid or bacteriologically acceptable salt of pyruvic acid at a level of from 0.1% to 1.0%. 
     
     
       27. The process according to claim 26 wherein the nutrient media contains from 0.5% to 0.8% pyruvic acid. 
     
     
       28. The process according to claim 19 further comprising the steps of separating out the diacetyl produced in step (c) and adding the diacetyl to a coffee product or imitation coffee product to enhance a buttery flavor in said product. 
     
     
       29. The process according to claim 28 wherein the level of addition of the diacetyl to the coffee product ranges from 0.1 ppm to 1.5 ppm on an as-consumed basis. 
     
     
       30. The process according to claim 28 wherein the separated diacetyl is added to a soluble coffee product at a level of from 10 to 150 ppm diacetyl on a dry weight basis. 
     
     
       31. The process according to claim 19 further comprising the steps of combining the diacetyl and nutrient media of step (c) with a concentrated coffee extract and spray drying or freeze drying the combination obtained therefrom to produce a soluble coffee. 
     
     
       32. The process according to claim 31 wherein the soluble coffee contains from 10 to 150 ppm diacetyl on a dry weight basis. 
     
     
       33. The process according to claim 19 further comprising the steps of separating out the diacetyl produced in step (c) and combining said diacetyl with a concentrated coffee extract and spray drying or freeze drying the combination obtained therefrom to produce a soluble coffee. 
     
     
       34. The process according to claim 33 wherein the soluble coffee contains from 10 to 150 ppm diacetyl on a dry weight basis. 
     
     
       35. The process according to claim 28 wherein the separated diacetyl is added to roast and ground coffee at a level of from 50 to 400 ppm on a dry weight basis. 
     
     
       36. The product produced by the process of claim 30.